Skip to main content
. 2023 Jan 26;61(1):2201117. doi: 10.1183/13993003.01117-2022

FIGURE 1.

FIGURE 1

Expired gas tracings from one patient: exhaled partial pressure of oxygen (PO2; top black line, red symbols and lines) and carbon dioxide (PCO2; bottom black line, blue symbols and lines). The second dotted line indicates the beginning of alveolar emptying (phase III), sloping dashed lines indicate the linear regression fits to phase III. Alveolar partial pressures (PACO2 and PAO2) were measured from the mid-volume of the linear regression fit to phase III (∼225 mL in this example). Filled symbols indicate mean alveolar values; open symbols indicate contemporaneous arterial values; arterial–alveolar differences are indicated by the solid vertical lines connecting the symbols.